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I've got a 94 integra ls turbo. I put toghter my own custom tubro kit but my first gear doesn't start to catch boost until 3700 and by the time I reach red line at 7200 its only at 6 pounds. I'm boosting 8 pounds. But all my other gears catch full 8 psi at around 4500. I've got 2.5 intercooler pipes and 2.25 downpipe to a 2.5 exhaust. In a couple of weeks I will be switching my downpipe to a 3.0. I've got a t3 garrett airresearch intake .48 exhaust.63. If any one knows how to fix this slow boost in first gear let me know.

thanks
 

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Its because there isn't much load on the engine compared to other gears. If you do some reading, you'll see that most any car will not make full boost by the time you have to shift out of 1st. The only way around it is with a 2-step.

Is your turbo really a .63 hot side with a .48 compressor? That is a weird combination; the .63 is a hair big for a 1.8L and the compressor is on the small side.
 

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its probably the combination that there isn't a whole lot of load in first to begin with, and the fact that you have 2.5" charge piping hurts you, takes you longer to spool. if it was 2.25" or even 2" your turbo would be spoolin' like a mofo
 

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On the other hand, many would say that turbo setups are not sensitive to the volume of the intake tract. I remember seeing a post where someone figured the extra volume from a bunch of exces tubing in relation to the turbo CFM. The time increase to fill the extra intake space was something like 0.4 second or less. Many also say that a good rear mount turbo setup only sees a marginal increase in lag. Just my experience. YMMV.

My SVO has a .60/.63 T3 and probably 300lbs more than an Integra, but it is still really hard to hit 14psi in first. Even second just barely gets there unless I'm going up a hill. It's not a "lag" issue either because if you bring the revs over 3000 with slight throttle and then flat foot it, the boost gage moves as fast as the pedal.
 

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its actually not the load...
its how long your giving the turbo to spool...

in 1st gear, i hit about 3-4 lbs when im boosting 11...

even 2nd doesnt catch full boost unless i come from 1st...


your turbo im guessing is just to big for what you want it to do...

i for one... dont need boost in first... so 3-4 lbs is good for me...
i start to spin at end of 1st, and spin all the way through 2nd... with usualyl 8-10lbs...
and 3rd hits 11 on the dime and spins till about 80....

boost lag is just suspensce..... :)
 

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gsrchad said:
its actually not the load...
its how long your giving the turbo to spool...

your turbo im guessing is just to big for what you want it to do...
Load on a non-direct injection engine refers to the throttle angle. The issue here is that WOT in first gear doesn't last long enough to produce full boost. In contrast, you will make full boost in neutral bouncing off the rev limiter.

Like I said, a .48 T3 compressor coupled with a .63 hot housing is lopsided. A .60/.48 would be better on a street car.
 
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